Bethesda MD -- Exactly what are the relationships among several factors: the supply of doctors, the composition of the physician workforce, the quality of health care, and overall health spending? This important set of questions is addressed in a package of papers and perspectives published today on the Health Affairs Web site. http://content.healthaffairs.org/cgi/content/full/hlthaff.28.1.w87/DC2

Health Affairs is publishing papers addressing this topic at a time when the United States faces a number of major and potentially competing challenges in health and health care. The incoming administration of President-elect Barack Obama and the new Congress are likely to contemplate a number of proposals aimed at improving the health status of the population; expanding health coverage and access to care; coping with a future of aging and chronically ill people; and constraining the growth of health spending. Meanwhile, organizations such as the Association of American Medical Colleges, alarmed at what they say is a looming shortage of physicians, have called for a 30 percent increase in medical school enrollments and additional federal support for residency positions in teaching hospitals.

Two papers in this Health Affairs package are by Richard "Buz" Cooper of the University of Pennsylvania's Wharton School, and they examine the relationships among the factors described above. Cooper argues that the nation is in "the throes of a deepening crisis" because of a shortage of physicians. In his first paper, he contends that states with greater numbers of physicians of all types, generalists or specialists, relative to the size of the state's population have better-quality health care. In a second paper, he argues that states with more total health care spending per capita have better-quality health care.

In two Perspectives on Cooper's work, Katherine Baicker and Amitabh Chandra of Harvard and Elliott Fisher, David Goodman, and Jonathan Skinner of Dartmouth take issue with Cooper's conclusions. They assert that Cooper's data suggest instead that the quality of health care is better in states with more family physicians only. By contrast, they say, Cooper's data do not show that greater numbers of specialists produce the same benefits of higher-quality care. Moreover, Skinner and colleagues assert that the weight of the evidence shows that high spending on health care is not associated with better care.

Against this backdrop, Health Affairs Editor-in-Chief Susan Dentzer explains in a "From the Editor" note, policymakers clearly need to understand how to best deliver high-quality health and health care, and whether or not the nation needs more physicians -- and of what sort -- to accomplish these goals. In a Preface to this Web-Exclusive package, Health Affairs deputy editor Philip Musgrove concludes that the debate over whether the U.S. has too many or too few physicians is not settled by these papers and Perspectives. However, the evidence suggests that having more general practitioners relative to specialists produces higher-quality health care.

How Many Doctors, And What Kinds?

In his first paper, Cooper takes issue specifically with a 2004 Health Affairs paper by Baicker and Chandra that found that "states where more physicians are specialists have lower-quality care." Because of this paper and citations of it in the academic literature and the lay press, Cooper says, "The notion that having more specialists is associated with poorer outcomes and that having more family practitioners is associated with better outcomes is ubiquitous. Yet it is incorrect. The reality is that states with more physicians per capita, both specialists and family physicians, have better-quality health care." http://content.healthaffairs.org/cgi/content/abstract/hlthaff.28.1.w91

Using somewhat different data sets from those used by Baicker and Chandra, Cooper examines the state-by-state relationship between the number of physicians per state resident and state health care quality rankings. For the state quality rankings, he employs two composite measures of quality -- one developed by Stephen Jencks and colleagues and used by Baicker and Chandra in their paper, and the other developed by the Commonwealth Fund. Cooper reports that states with more physicians tend to rank higher on both measures of quality. For the total number of physicians and for the number of generalists, the relationship to quality is statistically significant using both the Jencks and Commonwealth measures. But for the number of specialists, the relationship is statistically significant only using the Commonwealth measure, not the Jencks metric.

In their Perspective on Cooper's paper on physician supply, Baicker and Chandra zero in on the fact that using the Jencks scale, there was no statistically significant relationship between the number of specialists per capita in a state and its quality ranking. "A more careful statement [of Cooper's findings] would be, ‘Quality is better in states with more family physicians, but no significant association was found for specialists'," Baicker and Chandra argue. http://content.healthaffairs.org/cgi/content/abstract/hlthaff.28.1.w116

Baicker and Chandra also stress the importance of the mix of the physician workforce, not just its overall size. Cooper's own findings, they say, demonstrate that "generalists have a dramatically bigger effect on quality than specialists do." Simple visual inspection of Cooper's exhibits "suggests that you would have to add roughly ten specialists per capita to move up ten spots in the quality ranking, but you would only have to add one generalist per capita to move up the same ten spots," the two Harvard researchers write.

Does Higher Overall Health Spending Produce Better-Quality Care?

In his second paper, Cooper examines the relationship between state quality rankings and two measures of spending at the state level: per enrollee Medicare spending and overall per capita health spending. Like the Dartmouth researchers, Cooper finds an association between higher Medicare spending in a state and lower quality rankings. However, "a very different picture emerges when state quality rankings are compared with total health spending per capita," Cooper points out. He finds that quality increases as total per capita health spending at the state level, and non-Medicare per capita health spending at the state level, increase. However, he cautions against overestimating the extent to which higher spending leads to higher quality, since both spending and the quality of health care delivered are affected by a range of socioeconomic variables including income, race, education, and population density. http://content.healthaffairs.org/cgi/content/abstract/hlthaff.28.1.w103

Cooper writes that an association between higher Medicare spending and poorer quality has led the Dartmouth researchers and their colleagues to conclude that the additional Medicare spending represents waste and inefficiency. "However," he argues, "the observed relationship between Medicare spending and quality is principally due to the fact that many states in the South have high Medicare spending per enrollee but low health care spending per capita, and their poor quality correlates with their overall low levels of health care spending."

More broadly, Cooper argues, Medicare spending is a poor proxy for overall health spending because it is determined by peculiar legislative and demographic characteristics. There is no statistically significant correlation between Medicare per enrollee spending and overall per capita health spending in a given state. These points, together with the fact that total per capita health care spending at the state level is associated with better-quality health care, "should refocus thinking about the impact of health care spending on society, as politicians and the public prepare to address the vexing issues of national health care reform," Cooper concludes.

In their Perspective response to Cooper's paper on spending, Jonathan Skinner and coauthors argue that the state per capita health spending data that Cooper uses "is a poor measure of health care utilization, given its dependence on the age structure of the population and on indirect measures such as hospital business revenue from patient care." By contrast, the Medicare data used by Skinner and his Dartmouth colleagues "measure very accurately what doctors and hospitals do for their patients," allowing researchers to measure the association between the amount of care received and health outcomes. http://content.healthaffairs.org/cgi/content/abstract/hlthaff.28.1.w119

What's more, say Skinner and coauthors, simply taking into account the differences in median age among various states undermines Cooper's case by eliminating any statistically significant links between total spending in those states and the quality of care. In addition, both Cooper and Skinner and his colleagues agree that a large portion of the state-to-state variation in health care quality is determined by factors other than spending. Cooper points to socioeconomic factors such as income, race, education, and population density, whereas Skinner and coauthors point to "social capital," defined as "the extent to which residents of a state participate in civic activities, are well-educated, trust others, or engage in philanthropic activities."

Health Affairs, published by Project HOPE, is the leading journal of health policy. The peer-reviewed journal appears bimonthly in print with additional online-only papers published weekly as Health Affairs Web Exclusives at www.healthaffairs.org. The full text of each Health Affairs Web Exclusive is available free of charge to all Web site visitors for a two-week period following posting, after which it will switch to pay-per-view for nonsubscribers. Web Exclusives are supported in part by a grant from the Commonwealth Fund.